The embodiment relates to a wireless power transmission technology. More particularly, the embodiment relates to a wireless power transmitter of wirelessly transmitting electric power.
A wireless power transmission or a wireless energy transfer refers to a technology of wirelessly transferring electric energy to desired devices. In the 1800's, an electric motor or a transformer employing the principle of electromagnetic induction has been extensively used and then a method for transmitting electrical energy by irradiating electromagnetic waves, such as radio waves or lasers, has been suggested. Actually, electrical toothbrushes or electrical razors, which are frequently used in daily life, are charged based on the principle of electromagnetic induction. The electromagnetic induction refers to a phenomenon in which voltage is induced so that current flows when a magnetic field is varied around a conductor. Although the commercialization of the electromagnetic induction technology has been rapidly progressed around small-size devices, the power transmission distance thereof is short.
Until now, wireless energy transmission schemes include a remote telecommunication technology based on a magnetic resonance scheme and a short wave radio frequency scheme in addition to the electromagnetic induction scheme.
Recently, among wireless power transmitting technologies, an energy transmitting scheme employing the electromagnetic induction scheme and the resonance scheme has been widely used.
Since a wireless power transmission system based on the electromagnetic induction scheme and the resonance scheme transmits electrical signals formed at transmitter and receiver sides through a coil in wireless, a user can easily charge an electronic device such as a portable device with electricity.
However, according to the related art, heat is generated from the transmission coil included in the wireless power transmitter due to a resistance component when current flows through the transmission coil, so that the wireless power transmitter is deteriorated. Thus, the heat is transferred to the wireless power receiver placed on the wireless power transmitter, so that the wireless power receiver is deteriorated.
One example of the related art is disclosed in Korean Patent Unexamined Publication No. 10-2007-0080057 entitled “Contactless charger system having heat-dissipating means and charging unit thereof”.